[The estimation of the variation in the effective dose in the most frequent nuclear medicine studies].
BACKGROUND
The evaluation of effective doses in nuclear medicine investigations is generally referred to the average man, with no relevant associated diseases, during standard examinations. The effective dose in nuclear medicine examinations can be measured directly with ICRP 68. In clinical practice, the many variables related to patients characteristics and examination type may cause major differences between practical and theoretical doses. Thus, we investigated the factors which may affect internal irradiation in some of the most common nuclear medicine investigations.


METHODS
We analyzed the most frequent examinations carried out on 177 patients in the Nuclear Medicine Department of S. Anna Hospital, namely thyroid scintigraphy, total body bone scan, dynamic and static renal scintigraphy. The administered activity data were analyzed as a function of the withdrawn activity and that remaining in the syringe after i.v. administration and of time delays, and then they were submitted to statistical analysis (mean, standard deviation, 95% confidence range).


RESULTS
Equivalent and effective dose changes had no correlation with patient anatomy and associated diseases on the basis of history alone, while radiopharmaceutical preparation and administration methods exhibited a real influence on effective dose: the difference between nominal and administered activity ranged 11-14.5%.


CONCLUSIONS
The patients submitted to nuclear medicine investigations receive an effective dose ranging from < .5 mSv to > 4 mSv in total body scan. Our results, related to the different examination techniques, represent a confident evaluations of patient doses, as required by the relevant normative law.
Ostinelli
A
A
Servizio di Fisica Sanitaria, Azienda Ospedaliera S. Anna, Como.
Monti
A F
AF
Gelosa
S
S
Cacciatori
M
M
D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D008297:Male; D011829:Radiation Dosage; D011877:Radionuclide Imaging / Q000379:methods* / Q000706:statistics & numerical data; D013670:Sodium Pertechnetate Tc 99m / Q000008:administration & dosage; D019783:Technetium Tc 99m Dimercaptosuccinic Acid / Q000008:administration & dosage; D013669:Technetium Tc 99m Medronate / Q000008:administration & dosage; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage; D013961:Thyroid Gland / Q000000981:diagnostic imaging; D014915:Whole-Body Counting
D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D013670:Sodium Pertechnetate Tc 99m; D016284:Technetium Tc 99m Pentetate; D013669:Technetium Tc 99m Medronate
Valutazione della variazione della dose efficace nelle più frequenti indagini mediconucleari.